A locking device of this type is used, in particular, in order to equip a nacelle, intended for equipping an aircraft.
An aircraft is driven by means of a plurality of turbojet engines, each accommodated in a nacelle which likewise houses an assembly of accessory actuating devices associated with its operation and ensuring various functions when the turbojet reactor is in operation or at a standstill. These accessory actuating devices comprise, in particular, a mechanical system for the actuation of thrust reversers.
A nacelle generally has a tubular structure comprising an air inlet upstream of the turbojet engine, a middle section intended for surrounding a blower of the turbojet engine, and a rear section capable of housing thrust reversal means and intended for surrounding the combustion chamber of the turbojet engine and generally terminates in an ejection nozzle, the outlet of which is located downstream of the turbojet engine.
Modern nacelles are often intended for housing a double-flow turbojet engine capable of generating, by means of the rotating blades of the blower, a stream of hot air (also called a primary stream), coming from the combustion chamber of the turbojet engine.
A nacelle generally has an external structure, called an outer fixed structure (OFS), which, with a concentric internal structure, called an inner fixed structure (IFS), defines an annular flow channel also called a flow section, intended for channeling a stream of cold air, called a secondary stream, which circulates outside the turbojet engine. The primary and secondary stream which are ejected from the turbojet engine at the rear of the nacelle.
Each propulsive assembly of the aircraft is thus formed by a nacelle and a turbojet engine and is suspended on a fixed structure of the aircraft, for example under a wing or on the fuselage, by means of a pylon or mast attached to the turbojet engine or to the nacelle.
The rear section of the external structure of the nacelle is normally formed from one first and one second half shell of substantially semi-cylindrical shape, on either side of a longitudinal plane of symmetry of the nacelle, and mounted movably so as to be capable of being deployed between an operating position and a maintenance position for the purpose of giving access to the turbojet engine. The two half shells are generally mounted pivotably about a longitudinal axis forming a hinge in the upper part (at 12 o'clock) of the reverser. The half shells are held in the closing position by means of locking devices arranged at least along a junction line located in the lower part (at 6 o'clock).
The rear section and the middle section are linked by means of a fixed frame. The front edge of the rear section is an especially sensitive zone since it has means for positioning each half shell with respect to the fixed frame. As is known per se, these positioning means are formed by an annular rib of V-shaped profile and by a groove of complementary shape and profile. When the half shells are in a position close to one another, each rib is engaged in the corresponding groove, so that each half shell is held in position during the flight of the aircraft.
In order to hold the half shells in position, a locking device is provided in the region of the front edge of these, at least in the lower junction zone.
During flight, the walls of the nacelle are subjected to high stresses contributable to the passage of air or gas under pressure, so that it is necessary to provide an additional locking device intended for supplementing the abovementioned locking device in the event of a fracture of the latter.
Other locking devices are provided in the region of the lower junction zone, at the rear of the front edge.
However, the front zone of the rear section makes it possible to accommodate the pipework equipping the turbojet engine. Thus, the locking device equipping the front edge is arranged at a distance from the other locking devices, and it is therefore necessary to provide another locking device in the region of the front edge.
Owing the bulk of the abovementioned pipework, it becomes very difficult to equip the front edge with a complete additional locking device.